Enter full manual mode and press the info button.
Screen is shown with all the settings.
On my camera the speed is selected. this can be changed by rotating the dial.
To select the aperture press the +/- dial by the shuitter button. The selection goes to the aperture figure. Again rotate the the dial and the value changes.

Press the info button to return to norm.
Go to live view press !()! and you will see the settings along with the over/under exposure figure.